McKenna's Pharmacology for Nursing, 2e

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P A R T 9  Drugs acting on the renal system

KEY POINTS

■ ■ Administer the drugs with food to decrease GI adverse effects if they occur. ■ ■ Institute safety precautions if the person experiences CNS effects to prevent injury. ■ ■ Advise people to continue the full course of the drug ordered and not to stop taking it as soon as the uncomfortable signs and symptoms pass to ensure eradication of the infection and prevent the emergence of resistant strains of bacteria. ■ ■ Encourage the person to drink lots of fluids (unless contraindicated by other conditions) to promote flushing of the bladder and prevent urinary stasis , and to avoid citrus juices and antacids, which promote an alkaline urine and provide opportunity for bacteria growth. ■ ■ Provide or assist with perineal hygiene as indicated to reduce the risk of re-infection or prevent transmission of infection. ■ ■ Explain to people with chronic UTIs about additional activities that can facilitate an acidic urine to increase the effectiveness of urinary tract anti-infectives. ■ ■ Provide thorough teaching, including drug name, dosage, intended effect and schedule for administration; measures to prevent or alleviate adverse effects; the need to avoid foods that cause alkaline ash and produce an alkaline urine (e.g. citrus juices, antacids); the need to take the drug with food or meals to reduce GI effects; the importance of increasing fluid intake, including the use of cranberry juice; measures to prevent the recurrence of UTIs; and the need for periodic monitoring and laboratory testing such as urinalysis, urine culture and sensitivity to enhance knowledge about drug therapy and to promote compliance. symptoms); repeat culture and sensitivity tests as recommended for evaluation of the effectiveness of all of these drugs. ■ ■ Monitor for adverse effects (skin evaluation, orientation and reflexes, GI effects). ■ ■ Evaluate the effectiveness of the teaching plan (person can name drug, dosage, adverse effects to watch for, specific measures to avoid them and measures to take to increase the effectiveness of the drug). ■ ■ Monitor the effectiveness of comfort and safety measures and compliance with the therapeutic regimen. Evaluation ■ ■ Monitor the person’s response to the drug (resolution of UTI and relief of signs and

■■ Urinary tract anti-infectives destroy bacteria in the urinary tract that could be causing infections. ■■ Urinary tract specific antibiotics prevent bacterial reproduction and cause bacterial cell death. ■■ Some urinary tract anti-infectives kill urinary tract bacteria by acidifying the urine, making the tract a poor host for bacterial growth, or by killing the bacteria outright. ■■ Hygiene measures, proper diet and extra hydration are activities that help to decrease harmful bacteria in the urinary tract, which promotes the effect of urinary tract anti-infective agents. URINARY TRACT ANTISPASMODICS Urinary tract antispasmodics (Table 52.3) block the spasms of urinary tract muscles caused by various con- ditions. The antispasmodics that are available include darifenacin ( Enablex ), oxybutynin ( Ditropan ), toltero- dine ( Detrusitol ) and solifenacin ( Vesicare ) . Therapeutic actions and indications Inflammation in the urinary tract, such as cystitis, pros- tatitis, urethritis and urethrocystitis/urethrotrigonitis, causes smooth muscle spasms along the urinary tract. Irritation of the urinary tract leading to muscle spasm also occurs in individuals with neurogenic bladder. These spasms lead to the uncomfortable effects of dysuria (pain or discomfort with urination), urgency, incontinence, nocturia (recurrent night time urination) and suprapubic pain. The urinary tract antispasmodics relieve these spasms by blocking parasympathetic activity, thus suppressing overactivity, which leads to relaxation of the detrusor and other urinary tract muscles (see Figure 52.1). Because the parasympathetic system uses acetylcholine to cause its effects, these drugs are called anticholinergic drugs. See Table 52.3 for usual indications of urinary tract antispasmodics. Pharmacokinetics All of these agents are administered orally with the exception of oxybutynin, which is not only given orally but is also available as a dermal patch. These drugs are rapidly absorbed, have a slow onset of action and have a duration of action of 6 to 12 hours. Oxybutynin, when given by the transdermal system, has a duration of action of 96 hours. The system has to be replaced every 4 days. These drugs are metabolised in the liver and excreted in urine. They cross the placenta and are found in breast milk.